Ethanol is a 2-carbon alcohol with the molecular formula CH3CH2OH. It is an important industrial product nowadays and its importance is increasing. Ethanol can be produced by a chemical process or via biological processes, by fermentation of glucose containing substrate by yeast. The latter is often referred to as bioethanol. For ease of reading, in the present description ethanol is understood to be bioethanol, unless otherwise specified.
Ethanol finds different industrial applications. Firstly, it is used in the food and beverage industry. Ethanol can either be produced ‘in situ’ during fermentation processes like brewing and wine production or be produced as an end product of a fermentation process and subsequently added to beverages in order to produce alcoholised beverages. This ethanol is referred to as potable ethanol. Secondly, ethanol is increasingly used as an alternative energy source for fossil fuels. This ethanol is referred to as fuel ethanol or biofuel. It is less purified than potable ethanol but the production process is largely similar.
In some parts of the world, the use of raw materials for producing fuel ethanol puts the use of the same raw materials for food production under a lot of pressure. Also for this reason, it is important to increase the yield of current ethanol production processes.
Nowadays, production of ethanol as an end product uses yeast strains known as distiller's yeast. Some research work has been done in the field to develop yeast strains having increased alcohol tolerance, in order to increase the yield of ethanol production process. It is also known to use other yeast strains having a high alcohol tolerance, i.e. able to produce high amounts of ethanol, such as brewer's yeast.
DD253044A1 discloses the use of distiller's yeast and brewer's yeast in the production of ethanol.
There is an ever existing demand from industry to provide a process with increased yield and increased rate of ethanol production, without increased production costs. The present invention provides such a solution.